Equatorial alcohols, preparation by use

Epoxides from aldehydes, 46, 44 Equatorial alcohols, preparation by use of the lithium aluminum hydride-aluminum chloride reagent, 47, 19... 

The D-mannose subunit 23 (Scheme 5) was prepared from D-mannose itself. This was designed to use an acetate at C2 to control the stereochemistry of the disaccharide glycosyl-ation reaction. The precursor 22 was obtained by exclusive alkylation of the equatorial C3 alcohol. 

Intramolecular Diels—Alder reactions of ort/m-quinone monoketals into bicyclo [2.2.2]octane ring systems were also used by Chen s group in the three syntheses of the Fab-inhibitory antibiotic platencin (and analogues thereof) that they reported in 2011 [126]. For example, inspired by Liao s work, they prepared the phenolic (/ )-alcohol 227 (90% ee), which was treated with DIB in MeOH to afford the ortho-quinone dimethyl monoketal 228. This MOB was heated in toluene to trigger its [4 +2] cycloaddition, which preferentially occurred via a chair-like transition state displaying the OH group in an equatorial orientation (see 228 in Fig. 55) to furnish... 

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